Sunday, December 31, 2006
... /////

Figure 1: Cambridge Common: this is where George W. assumed leadership of the continental forces in 1775. Click to zoom in. Steven Pinker has a nicer but older snowy picture of the same area during the sunset.

It's nothing like the huge blizzard in 2005 and it is not as early as the snow in October 2005 but one thing is clear: snow is back in Boston. I used to think that it was impossible to take pictures at night but you can see a counterexample above. Everything is sharp except for the huge commuting yet non-commutative car that is stretched across another picture. The picture shows a world in which hbar is equal to 10,000 Joule seconds.

Saturday, December 30, 2006
... /////

The Iraqi prediction of string theory has been experimentally verified: according to many official witnesses, the closed string has indeed had a nonzero linking number with Saddam Hussein's neck. Because the paperwork, including the "red card" introduced during his own reign, has been completed, the executors could move closer to the singular point of the moduli space.

Video preview of the execution is here. The genuine video is at the bottom.

On one hand, this is very sad news and our sympathies clearly go to Saddam's loving daughter who has requested a burial of her exceptional father in Yemen. On the other hand, one can't forget that Saddam Hussain has been brutally imposing not only political correctness on his countrymates for decades. His 24 years show what kind of a government one gets if he promotes the minority rights above a certain level.

On November 5th, when his ultimate fate was decided, Saddam asked Iraqis not to hate those who came to liberate Iraq because hate does not leave space for a person to be fair. It makes one blind and closes all doors of thinking. This is an example how seemingly bad people may become very reasonable and morally elevated philosophers when they're properly dealt with.

Friday, December 29, 2006
... /////

If you think that the format and logic of this text is childish, I tend to agree. But it was invented by RealClimate.ORG, not your humble correspondent... ;-)The worst temperature news for the alarmists:

has something to say about it. They interview Shing-Tung Yau who describes some stories he had with Richard Hamilton. Yau corrects some of the myths spread by the journalists and a poem by Yau is mentioned. (Yau has also written a poem for the Becker-Becker-Schwarz textbook.)

Wednesday, December 27, 2006
... /////

One of the claims of the proponents of the catastrophic climate change theory is that the climate change is a killer. More concretely, the extinction of the Australian megafauna - including giant goannas, five-meter-long pythons, and huge kangaroos, lizards, and marsupials - used to be explained by the climate change because the dead animals looked dry and stressed. ;-)

New research shows that it was not the case. A January 2007 paper in Geology shows that the population of these big mammals was a nearly constant function of the climate: a wet climate is supposed to be better for them but they survived the dry periods without any problems.

As you can see, some contenders, especially the French and Czech ones, are older than from 2006. But they were mostly discovered by the readers of this blog in 2006 which is why they are legitimate competitors. ;-)

The first two papers were written by Pierre-Marie Robitaille, an influential experimenter from Ohio State University, while the last one is the work of Dmitri Rabounski. All of them are beautifully and professionally written and the first paper called "WMAP: a radiological analysis" contains nice pictures - both from astronomy as well as biology.

The only problem is that the content of all of them is complete nonsense. The first paper argues that the ☛COBE and ☛WMAP images do not satisfy the standards from NMR in medicine because of things like a low signal-to-noise ratio - such a low ratio that the medicine NMR people would be lost, he argues. ;-)

The following story is a typical example of the things that I viscerally dislike about the current Academia and one of the reasons why I am so looking forward to be gone. The story will show that a portion of the Academia is literally built on

corruption

parasitism

superficial people

hypocrisy

people who're not able to recognize that the behavior of others is just a matter of politeness

The person who will prove my point is Scott Aaronson but be sure that his example is far from an isolated anomaly. First, it is really not difficult to show that he doesn't have an infinitesimal remnant of scientific integrity. How is he deciding about the validity of particular statements in theoretical physics? Please don't read the text below if you just had your dinner.

I have therefore reached a decision. From this day forward, my allegiances in the String Wars will be open for sale to the highest bidder. Like a cynical arms merchant, I will offer my computational-complexity and humor services to both sides, and publicly espouse the views of whichever side seems more interested in buying them at the moment. Fly me to an exotic enough location, put me up in a swank enough hotel, and the number of spacetime dimensions can be anything you want it to be: 4, 10, 11, or even 172.9+3πi. ... I might have opinions on these topics, but they’re nothing that a cushy job offer or a suitcase full of “reimbursements” couldn’t change. ... Until then, I shall answer to no quantum-gravity research program, but rather seek to profit from them all.

It is absolutely impossible for me to hide how intensely I despise people like Scott Aaronson because this fact must be easily detectable by looking at my skin color and other quantities and observables. ;-) He's the ultimate example of a complete moral breakdown of a scientist. It is astonishing that the situation became so bad that the people are not only corrupt and dishonest but they proudly announce this fact on their blogs.

Did you ever worry that the last global warming skeptic is suddenly going to say Wow, now I see that they were right? Were you ever afraid that the last skeptic would post his own version of the hockey stick graph proving that the the climate was getting catastrophically hot in the 20th century?

Ladies and Gentlemen, the scary moment has arrived.

You can see that the 13th century was pretty warm but nothing can compare to the heat of the 20th century. The centuries before the birth of Jesus Christ are essentially counted using the Jewish calendar.

Click the graph to see an updated version together with an explanation what the numbers actually mean. ;-)

Paradoxically, the cause behind the blade is not global warming but rather global cooling. More precisely, it is a posting about global cooling. How can global cooling create such a horrifying hockey stick graph?

I was explained that the mechanism is called "instalanche" which is a portmonteau for "Instapundit avalanche" and you can Google out what it means. Well, Junkscience.com and 20+ other websites linking to the same posting have also contributed but those 13,000 visits a day still deserve to be called an "instalanche".

Wednesday, December 20, 2006
... /////

First of all, my thanks to Luboš Motl for his kind offer to host this text on the Reference Frame. Next, my apologies for the parts which you, the reader, may find either too trivial or too dense. Just skim the former, skip the latter (maybe returning to them later), and you'll be fine. As I am addressing a mixed audience, I'll consider it a success if everybody finds something different to complain about. - T.A.

Back to the future, Kantrowitz style

Unless you've been living under a rock lately, you know that NASA is going back to the moon in a big way. There is every reason to be excited about the reopening of the "high frontier", a term last heard in the 70s. While the past three decades have certainly seen great advances in the application of space technology to everyday life and science, most of that activity - and all of it involving humans - has been confined to low earth orbit. Mankind took a "giant step" back in the 60s, only to then retreat abruptly and stay put ever since. Why?

One of our popular topics for broader audience: today, Los Angeles International Airport matched the 1924 record low temperature of 39 degrees. Lancaster, a city in the high desert north of Los Angeles, shivered at 16 degrees Fahrenheit, two degrees below the previous record from 1965.

Napa's record for 12/19 from 1924 of 22 degrees has been broken, too. Monterey tied the 1948 record low temperature: the closer you're to the ground, the colder it grows.

Tuesday, December 19, 2006
... /////

It may be time for you to order Mark Srednicki's quantum field theory textbook. Amazon.com guarantees the lowest price once you receive it in January.

The book has been praised and celebrated by many people including Ann Nelson, Joe Polchinski, Wati Taylor (plus a few others, see the Amazon.com webpage), and readers of this blog. I am sure that most readers of this blog have already understood that the negative feedback from a certain notorious person is unjustified by anything.

This person hasn't seen the book and he is just emitting untrue ad hominem attacks against all physicists who are not afraid to say something that everyone knows, namely that this critic is not worth and capable of a serious scientific discussion.

Anita Gates in The New York Times reviews "Strings" that may be somewhat analogous to "Copenhagen" although it is probably not as good. They talk about quantum mechanics and string theory most of the time while a woman shared by two men is isomorphic to an electron shared by two atoms, the review says. ;-)

Adam Klasfeld offers something that I would call a positive review in TheaterMania.

Where? 78th Street Theater Lab, New York City.

Because this short article is about fiction, let me also mention a positive review of the book "Please, Mr Einstein" in San Francisco Chronicle. Albert Einstein is apparently still alive and he works on string theory, among other subjects, in an unspecified European city.

Paul Crutzen, the 1995 Nobel prize winner for chemistry, has used the state-of-the-art models to recalculate the potency of his plan to cancel the warming contribution believed by many to be caused by the enhanced greenhouse effect:

Crutzen's plan is to inject about 1 million of sulphur a year into the stratosphere. The added layer of sulphates located 10 miles above the surface would increase the reflectivity of the Earth and add a "positive cooling effect".

One million tons is a small fraction of our emissions of sulphates into the lower atmosphere today: sulphur is a common pollutant that has been a major cause of acid rains, among other things. Crutzen's recent paper about these artificial volcanos has made the debate about this old idea much more serious: his Nobel prize helps, too. Even some environmentalist organizations offered their measured support.

I personally think that only insane people can promote the very expensive "solutions" of the "problems" today when the climate is actually cooling on the annual basis, no climate problem exists, and the proposed solutions don't solve anything except for crippling the economic growth. A wiser attitude to these matters would be to wait at least for 10 more years. In these 10 years, some people would be competing in developing the best possible technologies to control the climate.

If you're also puzzled what's the brown rectangle: the picture is apparently a phone card. ;-)

Whenever I saw the trademark "Hanna-Barbera" as a kid, I was confused because Hana as well as Barbara are Czech female names. Twenty-four frames a second looked like even more incredible a task for two girls than for two men.

It is still mind-boggling that they have created so many images. One hour contains up to 86,400 pictures and the patience they needed had to be astronomical. It would be hard for me to create one picture like that: what about millions of pictures? Sure, there are some tricks to simplify the job and they hired other animators. But I still don't understand the computation that shows that such work ends up with a profit after a finite affine time.

In Pilsen, we could watch Tom and Jerry on German TV but most people didn't understand German. Most of us have thought that Tom and Jerry were German or at least I did. ;-) Even before the Velvet Revolution, some Western cartoons were aired on the Czechoslovak TV.

A position commonly found in public discussions, is that any new idea that is enough different, or even in opposition, to an established theory, would be morally “better”. But practically all such new ideas of laymen are really just simply nonsense. It is like claiming, for example, that my new “alternative Mars rocket made out from wood” would be better than a Saturn V, and going on at length about how the “establishment” would “oppress” my great idea. This appears as obvious nonsense to almost everybody, except perhaps to small kids and some desert tribes. As for alternatives to fundamental theories, the situation is analogous but unfortunately not as easily recognized by most.

An answer of a well-known critic of string theory:

By the way, as a kid I used to launch wood and cardboard model rockets and they went higher than metal ones. Wood’s a good material. Provide some calculation to prove it’s definitely better to use metal for rockets! Wooden rockets were used for a long time before metal ones. The latest technology in engineering and maths is not the best just because its the newest. That’s just as much a logical fallacy as ad hominem arguments.

Monday, December 18, 2006
... /////

As you may know, it was Baby Jesus - or Ježíšek - who brought Christmas gifts to the Czech children for centuries. The people in Austria and at least some regions in Germany agree: the gifts are brought by Christkind - the Christ child. Even though he should normally be invisible, you can find his picture at some websites:

Well, Christkind is actually female, unlike Baby Jesus, but the American readers will agree that it is not a serious difference.

The San Francisco Chronicle has a very entertaining article about the opposition faced by the fat, ugly, red guy who is now being successfully re-imported from America. I say re-imported because Santa Claus is a mutation of St. Nicholas who was promoted by the Dutch colonists in New Amsterdam (NYC). The modern Santa Claus was invented by CocaCola in 1931 to match the company's colors. He's now 75: congratulations!

Sunday, December 17, 2006
... /////

Michael Dine has written a book that will almost certainly become a new standard for all high-energy theorists who care about reality.

The 536 pages for $80 (Amazon.com guarantees the lowest price if you pre-order) that will be sold within weeks (and earlier in Great Britain) introduce the reader not only to field theory, the Standard Model, supersymmetry, grand unification, non-perturbative physics of gauge theory, and string theory. They not only answer all of her questions about the strong CP problem, the hierarchy problem, proton decay, anomaly cancellation, monopoles, technicolor.

They also show how supersymmetric gauge theories - and especially the MSSM - are constructed, how they behave for different numbers of flavors, how supersymmetry is broken, how N=2 supersymmetric theories can be solved. They also tell the beginner everything she wants to know about general relativity, cosmology, inflation, dark energy, dark matter, and astroparticle physics.

Saturday, December 16, 2006
... /////

According to the most recent data from the World Meteorological Organization (WMO), the year 2006 is set to be

colder than 2005

colder than 2004

colder than 2003

colder than 2002

... and, most obviously, ...

colder than 1998,

despite the new El Nino that has been warming the Earth again for a couple of months at the end of 2006 and that will probably continue in 2007. Yes, right now it seems that 2006 will become the coldest year among the most recent five years, and it will belong to the colder half of the years in the last decade.

The number of hurricanes in 2006 was below the long-term average. The total number of Atlantic tropical storms was the second lowest number during the last 12 years, after 1997.

Using the WMO terminology, 2006 is set to become the "sixth warmest year" after 1998, 2005, 2002, 2003, and 2004: see WMO's top five. Nevertheless, when a naive and innocent girl would read most of the newspapers, she would most likely start to think that we live in an era of a spectacular global warming. In reality, we live in an era of a spectacularly inexpensive propaganda produced by unusually blinded ... pundits.

Also, the new HadCru data released in January 2007 confirm the ordering of the years captured in the following graphs: the temperature anomalies from 1998 to 2006 were 0.526, 0.302, 0.277, 0.406, 0.455, 0.465, 0.444, 0.475, 0.422.

Figure 1: Global cooling. This graph, depicting 6 warmest years since 1998 according to their rank, shows how Al Gore and other people with comparable scientific standards would be presenting the recent temperature records if cooling or a new ice age became more convenient for their goals than warming.

Note that various tricks that are popular with some politicians and journalists-activists are used although not as intensely as in the media. The beginning of the graph is appropriately chosen. Some years that would lead to undesirable conclusions are removed. The decreasing links are emphasized and scientifically interpreted while the increasing links are suppressed and painted as scientifically irrelevant episodes.

Thursday, December 14, 2006
... /////

A discussion at Asymptotia.com shows what a waste of time it is to discuss difficult matters with people who are not capable or honest enough to learn the very basic pre-requisites for such a discussion.

A long "teacup" thread that currently contains 240+ comments has become a place to talk about the finiteness of perturbative string theory. There are many equivalent ways to calculate perturbative superstring amplitudes and many of them have been proven to be finite. Each approach has some advantages and some disadvantages. Different string theorists prefer different approaches but they don't have to agree on this question because formalism is not a part of physics: they only have to agree about the physical predictions such as the cross sections. And you bet they do.

The names associated with the available proofs of the finiteness include Martinec; Mandelstam; Berkovits; Atick, Moore, Sen; d'Hoker, Phong, and others. Some of these papers are more complete - or quite complete - or more constructive than others and there are various causal relations between the papers. Many of these results are secretly equivalent to each other because of the equivalences between the approaches that are demonstrated in other papers. Many of these papers were preceded by less successful papers or papers with flaws - flaws that were eventually fixed and settled.

Also, I assure Jacques that he has met people who consider Mandelstam's proof to be a proof, and besides your humble correspondent, this set includes Nathan Berkovits who confirms Mandelstam's proof on page 4 of his own proof in hep-th/0406055, reference 31, even though Nathan's proof is of course better. ;-)

Nancy Greene Raine is an alpine skier and an Olympic winner who has been voted to be Canada's female ahtlete of the 20th century. After she retired, she's been working to improve several ski resorts. This week, she will open a new Pontiac GMC Cup season. She is also the current chancellor of Thompson River University in British Columbia.

On the radio, she had the following to say about the global warming:

In science, there's almost never black and white. We don't know what next week's weather is going to be. To say in 50 or 100 years, the temperature is going to do this, is a bit of a stretch for me.

It is not only reasonable but it is also wise and probably true. Her statement can be supported by quantitative arguments rooted in physics or statistics. Indeed, the question whether the short-term uncertainties about the weather can be averaged out so that the long-term predictions can be trusted is a very difficult one.

Because no successful and non-trivial enough predictions of the long-term weather patterns have been made so far, it is very reasonable to think that we are not capable to do so at this moment. Also, Ms Greene Raine realizes that things simply can't be as black and white as some people would like to paint them.

But you can guess what such an innocent statement means in the present world: "furor on campus" as Kamloops Daily News, the local daily, called it. "Professors" - even though your humble correspondent would use somewhat less flattering words - immediately demanded Ms. Greene Raine's ouster from the ceremonial post.

Galileo Galilei's legal troubles resulted from his bold statements about the role of the Earth in the Universe, among other things. Larry Summers' troubles resulted from his guess that there could be cognitive differences between men and women. Ms Greene Raine's problems emerged after she said that things are not black and white and we should be more careful in making multi-decadal predictions if we can't do multi-week predictions.

Wall Street Journal thinks that her views are analogous to the views of Freeman Dyson and many others. But the message for Ms Greene Raine is clear: register the support for "good" environmentalists against "bad" skeptics, close your mouth, and submit to whatever prescription the Al Gores of the world prescribe for our salvation.

Imagine that you have to solve the following IQ test. Fill in the missing name:

???

Henry Kissinger

Madeleine Albright

No, the answer is not George Shultz who served in the Reagan administration. The correct answer is Lisa Randall. They're the guests of Charlie Rose from Tuesday to Thursday. Well, Lisa shared her time on Tuesday night with Edward Wilson who is a biologist at Harvard.

I am sure you must have seen Charlie Rose before because he's quite famous:

If you click the picture of Rose, you may watch the TV show via Video.Google.COM. It seems that Lisa did a very good job because a famous friend of extraterrestrial civilizations has been converted to extra dimensions.

When we say "string theory" these days, we mean the magnificent theory that can be connected by physical transitions to the well-known supersymmetric vacua in 10 or 11 spacetime dimensions: "string theory" really means "superstring theory".

But the whole first volume of Joe Polchinski's textbook, among others, is about bosonic string theory in 26 dimensions. Is it just an awkward and mostly inconsistent toy model to learn some techniques that reappear in superstring theory or is it a part of "the" theory that we study?

In 1993, Berkovits and Vafa argued that the N=0 bosonic string can be viewed as a special case of the N=1 superstring, much like the N=1 string is a special case of the N=2 string, by reinterpreting some matter degrees of freedom as the new required (super)conformal ghosts etc.

Tonight, Hellerman and Swanson claim that they can construct a cosmological solution that interpolates between the bosonic string in the past and the superstring (although it's just type 0 string) in the far future. Light-like tachyon condensates and the identification of the RG flow with a time evolution play a crucial role here.

Wednesday, December 13, 2006
... /////

a group theorist and knot theorist at Columbia University, published in the Notices of the AMS. A special comment for William Connolley: AMS doesn't stand for any climate crackpots; the acronym is nothing else than the American Mathematical Society.

She has a lot to say about her Russian, English, and Jewish roots; her sisters who were interested in math as well as hair; her job in the aircraft industry; her dislike for mathematical inequalities (I used to despise them, too); the interaction of her family and work; knots, braids, surfaces, modular groups, knot polynomials, invariants; collaboration in mathematics; NP completeness.

Officially, this interview is on-topic on this blog because its last pages are dedicated to women in science. She claims that the attitude towards women has changed enormously during her lifetime and mathematics is welcoming these days. Prof Birman rates Larry Summers' 1/14/2005 questions as very good ones and she is concerned that the political correctness has stopped many people from trying to understand these issues more completely.

The moment she really likes in mathematics is when she sees that someone has read and understood her work and if he or she could build on it.

Off-topic: a correction: several S.P. blogs have speculated that the owner of this blog is Leonardo DiCaprio whose name the CosmicVariance's sources can't even spell. The rumors are completely unsubstantiated. I am very far from DiCaprio in many respects and he is very far from me in other respects and, by reflexivity of the distance, sometimes even in the same respects. Don't believe the S.P. blogs. Thank you, The Kid. ;-)

Several recent discussions have convinced me to write an essay about the conventions and physics, with a focus on field redefinitions. The main question is:

Can a new set of conventions or coordinates reveal new physics?

The answer is essentially going to be

If you discover new physics using new degrees of freedom, new coordinates, new conventions, or new approach equivalent to the old one, it could have been harder and less natural to obtain the same results using the old conventions, the old degrees of freedom, and the old approach: but it would almost never be impossible.

If you agree with me, you don't really have to read the rest. But because some people might want to continue reading, I must write the rest of the article anyway.

By physics, I only mean the predictions of phenomena e.g. "Will the object XY explode if you do UV?" Clearly, not all of formalism is physics. Physical predictions are the quotient of all predictions of your theory modulo all details that you might have done differently. There is always a finite number of sign conventions and similar conventions in every theory. Once you fix them, infinitely many signs and other quantities can be predicted. Below, we will not talk about signs as much as about different coordinates and redundancies.

Classical physics

In classical physics, we have to work with configuration spaces "(x1...xn)" or phase spaces "(x1...xn, p1...pn)". In general, these spaces are manifolds and they admit many kinds of coordinates. We must be careful about the ranges for different coordinates and about all kinds of periodic identifications. But that's it. A description of a mechanical system such as the Solar System in terms of spherical coordinates is as good as the description in terms of spherical coordinates, among other examples.

In classical field theory, we can redefine not only the coordinates describing the spacetime itself but also the coordinates describing the infinite-dimensional configuration spaces of the fields. Any parameterization is good as long as it covers the physically interesting regions.

In general relativity, the coordinate reparameterization group is the group of the local symmetries of the theory. It can't be unexpected that we use all kinds of coordinates and indeed, the competition is much more severe. You can rarely say which coordinates are the best ones.

Coordinate singularities

Some coordinates behave nicely everywhere and the "local" physics - which either means "local" in spacetime or "local" some configuration space - follows some universal smooth laws that could have been determined by some general methods. But sometimes things can look bad. The metric tensor and other fields may diverge. There are cases in which this divergence is just an artifact of bad coordinates.

If you write the black hole metric in the original coordinates, it becomes singular near the horizon. Some components of the metric tensor go to zero and others go to infinity. Normally, someone could expect that no one knows what happens except that a classical general relativist knows what happens. She can find better coordinates in which the region near the horizon can be smoothly continued into the interior of the black hole. The horizon actually becomes a perfectly regular and ordinary place in spacetime. You can't even say whether you have crossed it or not.

A quantum gravity theorist may have some doubts about these statements and she can discover some new - probably tiny - effects that distinguish the interior of the black hole from the exterior that are probably necessary to solve the information loss paradox. Nevertheless, we still expect that the quantum gravity results will reduce to the classical general relativity results in the appropriate limit. Of course that we may be wrong but this "black holes don't exist" conclusion would represent a drastic violation of our intuition about locality of the laws of physics.

Imagine that the classical general relativist couldn't find the smooth coordinates. In that case, she would need to find some new laws describing what happens near the particular kind of singularity that is similar to the neutral black hole horizon. The answer to this question could potentially introduce another layer of arbitrariness to the theory. But the existence of better coordinates implies that no such arbitrarines exists near the black hole horizon and classical general relativity is able to predict the results of classical observations of infalling observers, too. It is merely a coordinate singularity.

Various sets of coordinates may suffer from various diseases. For example, a coordinate may be unable to describe physics outside the Solar System. If you insisted that this is a good coordinate, you would have to ask what happens when you reach the end of the world near Pluto or Eris. A whole new set of laws would be needed. For example, if you imagine that there is a gate to the Heaven at the end of the world, you would have to measure or calculate how many angels are employed as guards. These angels would become a part of physics. Such angels are not a real part of physics in any of the theories that have been considered important or true in the last 500 years or so because there always exist coordinates that cover all the relevant spaces.

Besides coordinate singularities, classical general relativity also leads to physical singularities. Some invariants such as the curvature invariants constructed out of the fields diverge. A better theory is needed. String theory is the only known theory - and arguably the only mathematically possible theory - that can give you answers what happens near such physical singularities. In some sense, you can view the physical singularity to be a coordinate singularity in some large configuration space in which you used coordinates that are only valid far away from the singularity.

String theory tells you to choose different degrees of freedom - and, let's admit, more degrees of freedom - near the singularity. It is actually important that the number of degrees of freedom is different because otherwise the legitimate physical diseases couldn't be cured. With the better string theoretical degrees of freedom, physics is again fully determined. String theory allows you to forbid the addition of new kinds of angels for every new kind of singularity. The actual physics around all these singularities is encoded in the same physical laws.

Hamiltonians and Lagrangians

Newton has found the laws of mechanics in terms of the differential equations. Some physicists and mathematicians after him were able to write the same equations in a more concise form, e.g. using the Lagrangians and Hamiltonians. Theorists love these newer approaches because of many reasons but it is fair to say that classical physics could be in principle done without them.

In quantum physics, we sometimes like the Hamiltonian formalism because the Hamiltonian becomes the operator that defines the time evolution. We could still define quantum mechanics in the Heisenberg picture in which the other operators are time-dependent, and write the appropriate differential equations for these operators without knowing that they can be obtained from a commutator with the Hamiltonian.

However, the fact that we know that the Hamiltonian seems to be behind all these equations in all the important cases changes our psychological perception of the space of possible theories and about the data we need to specify a theory. The Hamiltonian is surely a useful concept in many cases but in a very strict physical sense, it is not necessary.

Similar comments apply to the Lagrangians and actions. The laws of classical physics may be derived from the principle of stationary action. In quantum physics, we sum over all classical histories and the weight is determined by the classical action, as Dirac and Feynman have taught us. Feynman's approach is another, equivalent method to obtain the same amplitudes. And we use the same laws to compute the probabilities.

In this sense, once again, Feynman's approach is giving us a new picture to look at reality where various things may look more natural or less natural than before and where we think about different analogies from the everyday life. Many things are easier to deal with and other things may become more obscure. But the functional approach describes the same physics.

Redundant degrees of freedom

Feynman's approach makes Lorentz invariance in field theory much more manifest than the approaches based on the Hamiltonian. Also, it is priceless whenever we use redundant degrees of freedom. Electromagnetism was the first example of a physical theory in which redundant degrees of freedom were useful.

Historically, people would talk about "E" and "B" at each point because these electromagnetic vectors can be directly measured. But it was realized that the same physics can be encoded in the four-potential "A". Its values are not quite physical. Only "E" and "B" may be measured and there are many choices of "A" that give you the same "E" and "B". In quantum physics, the integrated "A" also matters modulo a periodicity - as explained by the Aharonov-Bohm effect.

Nevertheless, the electromagnetic potential became very useful even though nominally one of its off-shell components is unphysical and can be removed by a gauge transformation. The non-Abelian generalization of electromagnetism, the Yang-Mills theory, includes some extra Jacobians from the gauge-fixing. The path-integral approach makes the Lorentz-covariant calculations of Yang-Mills theories very convenient because these Jacobians can be accounted for by introducing the Faddeev-Popov ghosts, as Feynman figured out.

This is a whole new approach that has become so standard that most of us don't even know how to make the analogous calculations - including the Faddeev-Popov loops - in the Hamiltonian formalism. But it would still be possible although much harder because the manifest Lorentz symmetry would have to be sacrificed. In this jungle including the new unphysical friendly ghost fields, the physical states are obtained as BRST cohomologies of a nilpotent operator which can be seen to describe the same physics as the approaches without unphysical degrees of freedom.

The Batalin-Vilkovisky formalism extends the BRST formalism and allows you to include ghosts for ghosts which is very useful if the local symmetry itself becomes very complicated. If you need to know more about this difficult formalism, ask Dmitry Vaintrob. Still, things could in principle be done without these fancy machineries. However, it would be harder to correctly impose all the conditions such as unitarity and Lorentz symmetry.

Equivalent CFTs

In string theory we know a lot of dualities that are "hard": we can't even quite prove all of them in full generality because we don't have the full definition of string theory. Some of them can be proven in some particular backgrounds that are defined via the AdS/CFT correspondence or Matrix theory. For example, the U-dualities of M-theory on tori up to the five-torus can be proven from its Matrix-theoretical description.

These string dualities, to deserve the name, normally require at least one of the equivalent descriptions to be strongly coupled. We also know many equivalences on the worldsheet. Bosonic CFTs are equivalent to fermions which can be extended to interacting theories, different kinds of periodicity, and other cases. Many of the free theories are equivalent to non-linear sigma models on group manifolds, the WZW models, the minimal models - the canonical examples of well-defined theories that don't depend on a classical Lagrangian, and so forth.

Moreover, perturbative string theory allows us to depend not only on the RNS description but also on various alternative descriptions in terms of pure spinors, hybrid approaches, ghost pyramids, and others. All these approaches eventually agree on the physical spectrum and the particles' measurable interactions but they differ in their choice of the intermediate degrees of freedom, ghosts, and various redundant gauge symmetries. Each of them has some advantages and some disadvantages. All these differences can be described as technical differences although the technical differences may become very important if you actually need to complete a real calculation.

I could add a similar discussion about the unphysical choices we have to make when we regularize divergent expressions in quantum field theory, which can be done in many ways, and why these things are eventually irrelevant for the actual physical predictions due to the spirit of the renormalization group, at least within a certain error margin associated with effective field theories.

At any rate, I think that particle physicists and string theorists feel very strongly about the difference between new physical results - which is what really matters - and changes of formalism. From this viewpoint, one can't ever expect to get really new physics just by rewriting old physics in terms of unusual variables such as the BF theory. One shouldn't expect new physics from a parameterization of the momentum space by unconventional coordinates as they do in doubly special relativity either.

Unless you're lucky to guess new physics with the complete equations directly, new physics can only be revealed by identifying new possible principles, constraints, or physical mechanisms. A generic choice of new coordinates or a new selection of unphysical, redundant degrees of freedom is not quite new physics and we shouldn't expect that it can tell us something that we didn't know before.

Still, it is very easy to imagine that some of the new future important discoveries will sound like a mere conceptual breakthrough in the formalism. But in the string theory case, they must do more than just that in order to be really interesting. They must provide us with a key to easily transcend various approximations - weak coupling or a weak deviation from a superselection sector - that restrict our computational abilities today and that allow controversies about things like the vacuum selection problem to thrive. As we mentioned at the beginning, it is probably not impossible to find the new physical laws without a new, better formalism. But it could turn out to be damn hard.

Every person interested in theoretical physics at the technical level should buy this important update of older books such as the two volumes by Green, Schwarz, Witten.

The icon here links to the American Amazon.com where the book is going to be available in a few weeks. If you pre-order it, amazon.com guarantees that if the price drops before the book is sold, you will pay the minimum. See a list of similar books on string theory.

Sunday, December 10, 2006
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Some people only want to see bad things about him but I am convinced that the future historians will assign him a mixed sign in which the plus sign could dominate. (I am pretty sure that the Newsweek article about his death has been written and okayed long time before he actually died.) He took over when Chile was heading towards a real disaster, and not only because of the 500% inflation and supply problems. Let's look at the economy because it is a pretty well-defined thing, after all.

Normally we consider the hydropower plants to be environmentally friendly. However, when the greenhouse effect is counted as an undesirable process and when the analysis is made properly, things may look very different.

Did you think that the greenhouse gas emissions came from factories, power plants, cars, airplanes, cows, and sheep only? Think twice.

According to a fresh paper published in Taiwan, as well as similar reports released as early as in 2002, hydropower plants may be more potent sources of greenhouse gases even than oil-burning and coal-burning plants.

Organic materials are prevented from flowing down stream: they can't decompose and they cause emissions of methane and nitrous oxide. One ton of methane causes the same greenhouse effect as 21 tons of carbon dioxide while one ton of nitrous oxide causes the same greenhouse effect as 200 tons of carbon dioxide so you should better not neglect these gases if you didn't neglect CO2.

The message is very clear. If we listen to some of those politicians who are out there and if the greenhouse gases are eventually labeled as pollutants, we will have to start to exterminate all cows, sheep, and other mammals and demolish all power plants including the hydropower plants. Think twice.

Saturday, December 09, 2006
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One of the topics raised by the recent Joe Polchinski's review that led to some continued discussions is the topic of the hypothetical violations of the Lorentz symmetry and various proposed modifications of special relativity such as the so-called doubly special relativity or deformed special relativity. See cosmicvariance.com and backreaction.blogspot.com.

Figure 1: Discovery space shuttle took off again tonight. With a good enough eyesight or digital camera, you could see it from Boston, Copley Plaza. Can you find it on the picture?

I view these speculations as another example of unmotivated, bad physics, and a waste of paper. Let me explain why.

Back to 1905

First of all, Einstein's discovery of special relativity in 1905 was the real beginning of modern theoretical physics. Einstein was able to discover the true kinematics of space and time that morally respected the previously believed symmetries of Nature and that preserved the degree of their symmetry but it extended their validity. Einstein strengthened some of the holy principles of the physics before him - in fact, he modestly described special relativity as a minor update of Newton's framework; what he abandoned were assumptions that were so obvious to everyone that they didn't even doubt about them in public.

Thursday, December 07, 2006
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Joe Polchinski, one of the key physicists behind the second superstring revolution and the main father of D-branes, agreed to review two recent notorious physics books for American Scientist. And I would say that he did so in the characteristic old-fashioned perfectionist Polchinski fashion. ;-)

His 25 kilobytes of text or so describe some of the most universal errors, misconceptions, and misleading statements in these two books, together with Joe's own viewpoint on many of these broader questions about physics and together with some kind words. It is an interesting reading.

Joe Polchinski became a guest blogger with one of our potential competitors. No doubt, he has added some fuel to the controversy as some people call it. But when the fuel is added properly, it can sometimes burn the garbage into water and pure carbon dioxide which is a friendly gas that we call life. Let's hope that this environmentally friendly scenario will work out in this case. ;-)

Below, you find links to the paperback edition of Joe's book.

.....

Polchinski praises Smolin's description of the enthusiasm during the first superstring revolution. Then he shows why Smolin's statement that string theory predicted that the cosmological constant couldn't be positive is the first big myth of that book: the Maldacena-Nunez paper requires a special discussion at this point. Joe remembers the assumptions that went into their theorem and the fact that everyone always realized its limitations.

Polchinski continues by debunking various strange and clearly incorrect constructs of Smolin about holography such as "unpredictive" Maldacena's correspondence or "non-quantum" Maldacena's correspondence or "weak" Maldacena's correspondence and many others: much like I have explained in the review of Smolin's book (remember my analogy with the weak Darwinism?), Polchinski also clarifies that it is not possible to define any "weaker" version of Maldacena's duality that wouldn't be falsified by the known tests. More concretely, the conjecture crucially depends on quantum mechanics and it cannot break beyond the classical limit in any sense.

in the paper linked above to be published in Journal of Physics G in January 2007. See their self-promotion at the University at Buffalo: thanks to James O'Leary for his real insider corrections. A nuclear physics experiment with lead is claimed to have observed many axions decaying into electron-positron pairs. The axion lifetime should be a fraction of picosecond and the mass is around 7 MeV and 19 MeV (two different signals).

The only thing I can say is that it looks strange to me. The previous articles about axions were focusing on

Wednesday, December 06, 2006
... /////

It is often implicitly assumed or even explicitly said that the emissions of the greenhouse gases are caused almost exclusively by industry, traffic, and other artificial machines and devices. Well, that's not true because the greenhouse gases are also important products of processes that we call life. According to a new U.N. report, farm animals - mostly cows and sheep - account for

9 percent of carbon dioxide

40 percent of methane

65 percent of nitrous oxide

...

20 percent of the overall induced greenhouse effect.

In some countries such as New Zealand, this percentage is not 20 percent but around 33 percent. Also, the U.N. predicts that the meat production will double by 2050. In these technical matters, you may want to remember that the gases are emitted by the mouth of the cow, not the opposite side, because the fellow mammal has four stomachs. ;-)

The cow population may grow but doesn't have to grow. Those who call for downright reductions of greenhouse gas emissions effectively advocate a huge cattle holocaust - and indirectly, through the hunger of non-vegetarian humans, also a holocaust of men and women - and those who call for reductions in some sectors only are biased and unfair.

Instead of looking into the future, we can also organize our ideas about these matters by looking into the past. If there ever were a period in which the number or the total mass of large animals exceeded the current numbers five-fold, which is far from impossible because homo sapiens has removed quite a significant fraction of animals at many places, ordinary life in such a period generated more greenhouse gases than all of the current civilization.

Raman Sundrum gave a very charming talk whose goal was to refine a crazy way to solve the cosmological constant problem.

Unbroken supersymmetry may explain why the vacuum energy is zero. But because we know that the supersymmetry must be broken, the predicted vacuum energy after SUSY breaking seems to be far too high, by 60 orders of magnitude. That's better than the 120 orders of magnitude at the beginning but it's still bad, a person who wants to promote a weird alternative to SUSY such as Raman would argue. Also, we know that what we want is a much smaller but nonzero vacuum energy.

His favorite models cancel the contributions of ordinary matter to the vacuum energy - from the zero energy of the harmonic oscillators, so to say - by a new kind of matter that has the same statistics but that has the opposite sign of the energy. The Standard Model as well as the ghost Standard Model preserve the Lorentz symmetry but they must be coupled via gravity and it is this gravitational sector that has to break the Lorentz symmetry for this picture to work, Raman concluded.

Some of the ghost gravity models he considers are called the Frank Einstein theory or Frankenstein theory for short. ;-)

In his most realistic models, he chooses a rather generic Lorentz-violating action for the gravity modes - or scalar modes in a toy model. The form factors are suppressed in the spatial dimensions - by "exp(-p^2)"-like factors - but not in the temporal dimension. That's more than enough to make the loop diagrams converge. The radiation modes of gravity remain relativistic in their essence while the other components of the metric tensor are converted to strange non-local fields analogous to fields associated with rigid balls that induce the action at a distance and whose propagators don't depend on the energy "p^0".

Tuesday, December 05, 2006
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The ILC could be Chinese, after all. The text also illuminates why Sheldon Glashow - who is celebrating his birthday today, congratulations! - couldn't accept string theory: he worked on science compatible with the Cultural Revolution - a model with a Leninist matryoshka onion structure of matter - and proposed a name for a new particle inside the electron called the Maon after Mao Zedong. ;-)

Dmitry "Mitka" Vaintrob, 18, accepted the $100,000 Siemens competition award at New York University. His project was about string topology, more precisely

The string topology BV algebra, Hochschild cohomology and the Goldman bracket on surfaces.

Congratulations to Dmitry. I hope that all readers will understand the abstract. His victory shouldn't be unexpected especially because he looks like Brian Greene a bit, doesn't he? ;-) I am sure you will know which one he is on the picture.

Mathematics or mathematical physics don't have to be a financial disaster as long as you stay at the high school. :-) But don't get a false impression here. The money must be used for higher education.

...

Mitka is looking at Harvard at MIT for further mathematical adventures.

At asymptotia.com, a well-known critic of science has pre-emptively attacked Clifford Johnson and "accused" him and others of the intent to pretend that string topology is a kind of part of string theory. What a crime. ;-)

I happen to think that string topology is indeed a subset of mathematics inspired by and relevant for string theory such as Gromov-Witten theory, topology of moduli spaces and spaces of paths etc. as organized by topological string theory and topological field theory. Why do you think that string topology is called string topology and not quantum graphity topology, among other choices?

Look at a review of string topology and count how many times it talks about D-branes, sigma-model, Witten, Dijkgraaf, and other things. How could it *not* be a part of broader string theory? The degree of irrationality of some people's assertions is simply astonishing.

I agree with many commentators that these plans are not necessarily the most scientifically profound projects. Nevertheless, I tend to think that the mankind must eventually deal with the huge Universe. This feeling of mine may be an artifact of the romantic influence of science-fiction novels and movies. Nevertheless, the human ability to colonize the Universe should start to increase again, shouldn't it?

Stephen Hawking has recently reiterated his calls to occupy other solar systems in order to escape various lethal threats that are waiting here on Earth in the long term, such as bioterrorism. But even if you don't share his cataclysmic visions, shouldn't one of the goals of the civilization be to fight with the emptiness of the outer space?

Hawking vs. limited journalists

Incidentally, because I mentioned Stephen Hawking, you may look at the kind of battles that he is sometimes having with people whom he has identified as failed intellectuals. One of them just wrote in The Times that he is proud about the badge because he thinks that all intellectuals are failed ones. Well, in some other cases it depends on how you measure it. ;-)

You may read the throroughly incoherent pile of nonsense by Mr. Bryan Appleyard to see why Hawking's label for such people certainly doesn't belong to one of the few mistakes that Hawking has made in his life. Quite on the contrary: Hawking is right on the money.

Mr. Appleyard apparently thinks that he has found an argument showing that physics is just like religion or philosophy and that the theory of everything or the universal laws of physics can't exist: and the question whether M-theory is correct is, according to Mr. Appleyard, "meaningless". Absurd conclusions, indeed.

This journalist also believes that science must be a narrow, humble, small, non-adventurous, and unexciting - which is why he also criticizes Richard Dawkins and Steven Weinberg. On his easy-to-find blog, you may also learn that no one in the world knows what the LHC is good for. Well, in both characterizations of this paragraph, the journalist has probably confused science and the LHC on one side and himself on the other side. It's not the same thing.

Among the biologists, it's not just Richard Dawkins: most of important biologists I know of are listed as members of Al-Science, analogous to Al-Qaeda, in a 2003 article by this journalist that complained about the "science mafia". The journalist heroically wanted all these scientists to admit that science was impotent in all big questions, and because he failed, he at least wrote that rant in The Sunday Times because this is what a failed intellectual can always do. When you read it, you may become nostalgic about these old good times when aggressive crackpots were still treated just as aggressive crackpots.

But let me return to his newest "work": Couldn't please someone try to kindly explain these journalists that they're lacking at least 30 IQ points and 10 years of education to be able to judge whether Stephen Hawking should receive a science medal for his cosmological theories or not?

Monday, December 04, 2006
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Hugo Chávez, a key member of the rogues' gallery of the current world and a charismatic communist, has won six more years to transform Venezuela into a communist totalitarian country (61 vs 38 percent). The victory is a result of his oral skills and recent high oil prices that oil-rich countries such as Venezuela enjoy. Here he is with some of his friends. What kind of hovada they are. ;-)

Venezuela has become The Bolívarian Republic of Venezuela in 1999 when he took over. In practice, this means that the country is a soon-to-be Stalinist and anti-American dictatorship that follows the ideology of Noam Chomsky, among others.

Linguistically, it is named after Simón Bolívar. This important Latin American politician and the author of the first important 19th century Latin America constitution was a huge supporter of the free market and an admirer of the American revolution. He was reading books by Adam Smith, one of the main intellectual pioneers of capitalism, whenever he could. Moreover, Bolívar was viscerally hated by Karl Marx. 175 years after his death, his name has been hijacked by the communists. Poor Simón Bolívar.

Meanwhile, Auguste Pinochet who saved Chile from the development towards communism under Salvador Allende, a Marxist president who brought a 500% inflation and supply shortage to the country, and who had to introduce a highly problematic yet temporary rule of a military board responsible for many wrongdoings - a board which, however, made Chile thrive - has suffered a massive heart attack. The Reference Frame wishes him a speedy recovery.

published in Environmental Geology 50 (Springer-Verlag) in Summer 2006 they looked at various sources of changes of the global climate from a very unconventional perspective. They argue that the humans are responsible for 0.01 Celsius degrees of warming from the 0.56 Celsius degrees warming during the 20th century. Geophysical sources of temperature periodicity such as tectonic pressures and the solar factors are by 4-5 orders of magnitude more important than the anthropogenic effects, they argue in sentences that are hard to believe and that will be especially hard to believe for generic members of the climate science community where a strikingly contradictory hypothesis has recently become very popular.

Their estimate of the modulation of the temperatures due to the changing orbit of the Earth and its fluctuating eccentricity is 7.5 Kelvin degrees. Well, I would be careful before accepting any of these numbers, but it could be a mistake for the climate scientists not to look at their reasoning.

You will see many graphs of various quantities at geological timescales as well as the recent instrumental record plus the cooling in the last 1000 and 3000 years.

Saturday, December 02, 2006
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If string theory is a real theory of everything, it should explain not only why the particles and forces are what they are, what happens with the information inside a black hole, how did the Universe begin, and why there are so many electrons and so many obnoxious crackpots in the world: it should also unify and "explain" all important structures in mathematics. No one can guarantee that this unification of physics with mathematics is what is going to happen except that it does seem that it will happen and it has already happened in various special cases.

Classification of simple finite groups

Groups are extremely important and natural mathematical structures and the finite groups seem to be the simplest subclass even though their understanding is not easy, as we will see instantly. A very important subclass of the finite groups seem to the simple finite groups: those that contain no normal subgroups i.e. subgroups that are invariant under the conjugation by any element of the large group as a set. All other groups can essentially be expressed as direct or semidirect products of the simple finite groups: they depend on the simple groups.

The classification of simple finite groups took many decades (1955-1983) and thousands of pages had to be filled with mathematics. The result of this collective enterprise is an "enormous theorem" as it is often called. Because the amount of knowledge that has to be verified and connected - and, arguably, has been verified and connected - is large, there remain skeptics who are not sure that the full proof has indeed been completed: Jean-Pierre Serre is a prominent skeptic.

Skepticism aside, the results say the following. A simple finite group must be isomorphic to a group in one of the following families:

the cyclic groups "Zp" with a prime integer "p" - the simplest Abelian groups with "p" elements you can think about

the alternating groups "An" of all even permutations of "n" elements for "n" greater than three (because "A2" is trivial and "A3" is "Z3"); note that the symmetric group "Sn" of all permutations is a semidirect product of "An" with "Z2"

the groups of Lie type - essentially Lie groups with integer or rational entries of various kinds; this family includes both classical groups (projective, special unitary, symplectic orthogonal, and unitary over a finite field) as well as exceptional or "twisted" Lie groups over discrete fields

Tits group that is sometimes included into the previous family because of its indirect relations with F4, but sometimes is counted as the 27th element of the next family

26 sporadic groups

Note that the word "sporadic" is "doubly exceptional" because the exceptional Lie groups only lead to "easy" finite groups of Lie type. At any rate, the sporadic groups are the real gems that were identified and listed by the classification of finite groups. They are named after various mathematicians and in most cases, they have been written in terms of a few generators once we specify which products of these generators are equal to the identity element - for example, "ap=1" for "Zp".

You will see Wilczek playing the piano and both of them explaining their stories. Gross also mentions his foolish former colleague from Princeton who said to Gross a few months after their discovery that the theory could be nice but it could never be verified in Gross' lifetime.

Friday, December 01, 2006
... /////

during the Duality Seminar. As you may know, Frederik is the main guy who discovered the split black hole solutions and we should start with some general background for all these considerations which will be the main part of this article because of the general audience of readers of this blog and because some of the newer work is work in progress.

Split attractor flows

You may imagine that the popular spherically symmetric black holes are analogous to atoms. Frederik's split flow black holes are molecules: you may imagine that they are bound states of the "atomic" black holes - where the atoms sit at the minimum of a potential - and he has found precise solutions for them.

He has shown that for every attractor flow tree, there exists exactly one multi-centered black hole solution, a black hole "molecule". Let's explain what is the attractor flow tree.

Start with type IIA string theory on a Calabi-Yau three-fold: at low energies, this gives N=2 supergravity in d=4. The charges are carried by the D0, D2, D4, D6-branes. Call the total charge of a black hole Gamma which belongs to the lattice of even-dimensional homology. It has been known for some time that the moduli from the vector multiplet approach special values - the attractor values - as you go closer to the horizon.

The 2006 Atlantic hurricane season officially ended yesterday. We have seen nine storms. Five of them were hurricanes and two of those were "major hurricanes" although both of these Category 3 "major hurricanes" only exceeded the "major" threshold by a tiny amount.

All these three numbers are below the average of the last 50 years. The spring predictions of the hurricane center were higher by a factor of 2 or more. It's even more interesting to see the damages expressed in 2005 U.S. dollars - the approximate numbers are according to Wikipedia:

1998: 14 billion

1999: 7 billion

2000: 1.3 billion

2001: 7 billion

2002: 1.3 billion

2003: 4 billion

2004: 43 billion

2005: 120+ billion

2006: 0.18 billion (later raised to 0.5 billion)

No kidding, the damages decreased by more than two orders of magnitude from 2005, and they were by about 1 order of magnitude smaller than almost all other years. The previous silent season was 1997 which was comparable to 2006. Most recent years before 1997 caused multi-billion damages, too.

If someone happened to be interested in science, the reason for a weak 1997 season was really the 1998 El Nino. We have lived with another El Nino for two months or so and this El Nino has eliminated all conceivable tropical storms since October 2nd when Isaac disappeared.